This invention relates to a submersible pump system and more particularly to buoyancy controlled submersible pump system with a built-in capability for resurfacing for servicing or recovery. The submersible pump system may rest upon the bottom of a lake or other liquid medium or it may float in a suspended or neutrally buoyant position. Further yet, this invention relates to a linear electrofusion method.
Submersible pumps are typically submerged in a body of water such as a lake, stream, river or pond for irrigation or water supply. These submersible pumps have limitations. Some submersible pumps rest directly on the bottom of the body of water where there is a greater chance of ingesting debris. Other pumps rest upon a sled, which has runners in contact with the bottom. Of the sled variety of submersible pumps, some are made of lightweight materials and others are made of metal. In all variations, retrieval and servicing present a problem. Currently available submersible pumps do not have the built-in capacity to be resurfaced for servicing. Rather, they must be physically pulled out of the body of water in which they reside by a cable or other line. Further yet, current systems using multiple pumps with header assemblies typically require accessing all pumps to service a single pump. The only way to service a single pump is to remove the entire header assembly which results in the exposure of all of the pumps.
Current submersible pump systems do not have the capability to either float at various depths or create neutral buoyancy. The ability to have a variable buoyancy submersible pump at various levels is both required and highly desired. For example, a floating submersible pump is desired for obtaining drinking water from a lake. Many people have experienced the taste of the water when a lake “turns over.” Lake “turn over” occurs when the surface water of a lake, having higher density than the lower levels, due to temperature or seasonal changes, replaces the lower less dense water. This “turn over” often creates unpleasant tasting. Since current pumping systems are fixed in place, the pump cannot be raised or lowered to optimize intake of the freshest water.
Yet another limitation of existing submersible pumps is the flow volume capacity. Most of the submersible pumps have a flow volume capacity below 2,000 gallons per minute. While land based systems and permanently fixed subsurface systems provide more than 2,000 gallons per minute, these systems cannot be floated or resurfaced for servicing or moving for more preferential water intake.
In one aspect, manufacturing limitations have precluded development of pump assemblies necessary to overcome these problems. For example, the ability to linearly fuse, or weld, two or more thermoplastic components, items or products does not exist. Methods do exist to fuse ends of thermoplastic components, items or products. However, the state of the art has been limited to circumferential electrofusion of thermoplastic pipes. Electrofusion across a linear segment has been limited due to unequal heating and poor distribution of power. To achieve linear connectivity of thermoplastic components, items or products the industry uses spot welding or externally bands the same together.
In order to satisfy the needs of the industry, the current invention provides a buoyancy controlled submersible pump with the built-in capability of being re-floated and having both a simple buoyancy control and variable depth buoyancy. Additionally the present invention enhances serviceability by permitting service of a single pump out of many without having to remove a header assembly. The present invention also provides a submersible pump capable of delivering liquid at a rate of less than 50 gallons per minute up to at least 12,000 gallons per minute. Further, this present invention provides a method for the linear fusing of thermoplastic components, items and products.